JP3067705B2 - Scanning electron microscope - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a scanning electron microscope, and more particularly to a scanning electron microscope having a "function of minimizing image deterioration due to the influence of a magnetic field and vibration" during image observation.

[0002]

2. Description of the Related Art FIG. 4 is a block diagram showing a conventional scanning electron microscope. As shown in FIG. 4, a conventional scanning electron microscope includes an electron gun 2 for generating an electron beam 7 and an electron lens 3 for focusing the electron beam 7 on a sample 1.
A polarizing coil 4 for electrically scanning the focused electron beam 7 at an arbitrary position on the sample 1, and a secondary coil 8 for detecting secondary electrons 8 generated from the sample 1 by irradiating the electron beam 7. It has a secondary electron detector 5 and an observation CRT 6 for superimposing a plurality of times of secondary electron data captured by the secondary electron detector 5. In addition, 9 in FIG.
This is the stage on which

A conventional scanning electron microscope has the above-described configuration, and takes in secondary electron data generated from a sample 1 a plurality of times and superimposes them to perform image observation.

[0004]

As described above, in the conventional scanning electron microscope, the secondary electron data generated from the sample 1 is captured a plurality of times during image observation, and the observation is performed by superimposing the data. There are the following problems (1) and (2) when taking in data a plurality of times. (1) The electron beam 7 is changed irregularly due to the influence of the magnetic field generated from nearby equipment and the like, and as a result, there is a problem that the secondary electron data captured a plurality of times varies. (2) The sample and the like vibrate under the influence of vibrations such as floor vibrations and sound waves (air vibrations), so that there is a problem that the secondary electron data captured a plurality of times also varies.

The present invention has been made in view of the above problems (1) and (2), and has as its object to utilize secondary electrons generated from a sample by a scanning electron microscope. When performing image observation, a scanning electron microscope that minimizes the "effect of magnetic field and vibration" when capturing the secondary electron data multiple times, minimizes image degradation, and enables clear image observation To provide.

[0006]

The scanning electron microscope according to the present invention comprises an electron gun for generating an electron beam and an electron lens for converging the electron beam on a sample, similarly to the conventional scanning electron microscope. And the focused electron beam,
A polarizing coil for scanning to an arbitrary position on the sample,
A scanning type having a secondary electron detector for detecting secondary electrons generated from a sample by irradiating an electron beam, and an observation CRT for superimposing a plurality of times of secondary electron data captured by the secondary electron detector. It is an electron microscope, and furthermore, it has a magnetic field sensor that detects fluctuations in the magnetic field and a vibration sensor that detects vibration. ・ Monitors the magnetic field and vibration when capturing image data. The scanning electron microscope is characterized by having a function to judge whether or not it is affected by the noise and a function to delete data, thereby enabling observation with image data in which noise components are minimized. .

That is, the present invention provides a method of “irradiating a sample with an electron beam, capturing secondary electrons generated from the sample by a secondary electron detector, converting the amount of the secondary electrons into brightness of a cathode ray tube,
Magnetic field measuring means for detecting fluctuations in the magnetic field and vibration for detecting vibration
In a scanning electron microscope equipped with dynamic measurement means and observing an image , continuous magnetic field data and
Monitor vibration and vibration data, and
The magnetic field data at a predetermined detection point
And whether the vibration data is within or outside the standard
Image data deleter for deleting data outside of the standard value
Image with only data within the specified value
Is displayed on a CRT for observation . (Claim 1) as "Matters specifying the invention."

In the scanning electron microscope according to the present invention, magnetic field data and vibration data are monitored when an electron beam is scanned and secondary electrons from a sample are detected. At this time, the standard values of the magnetic field and the vibration are set (the standard values can be set freely), and it is determined whether the data is within the standard or out of the standard, and the non-standard data is deleted. Only the data within the standard is superimposed, and the image is displayed on the observation CRT.
Accordingly, noise components due to magnetic fields and vibrations can be minimized, and a clear image can be displayed.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments (first and second embodiments) of a scanning electron microscope according to the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram of a scanning electron microscope showing one embodiment (first embodiment) of the present invention. In the scanning electron microscope according to the first embodiment shown in FIG. 1, similar to the conventional scanning electron microscope,
An electron gun 2 for generating an electron beam 7, an electron lens 3 for focusing the electron beam 7 on the sample 1, and an electron lens 3 for electrically scanning the focused electron beam 7 at an arbitrary position on the sample 1. A polarizing coil 4, a secondary electron detector 5 for detecting secondary electrons 8 generated from the sample 1 by irradiating the electron beam 7, and a plurality of times of secondary electron data captured by the secondary electron detector 5 And an observation CRT 6 to be superimposed.

In the first embodiment, the scanning electron microscope having the above configuration incorporates the "magnetic field measuring device 10 and the vibration measuring device 11", and has a "determining device 12". It is a scanning electron microscope. That is, as shown in FIG. 1, a “magnetic field measuring device 10 for detecting a change in a magnetic field” near the focused electron beam 7 and a “vibration measuring device 11 for measuring vibration” on a stage 9 on which the sample 1 is mounted. Is established,
The magnetic field data and the vibration data are monitored by the magnetic field measuring device 10 and the vibration measuring device 11, and the data are linked with the data of the secondary electrons 8 from the sample 1 to judge the "acceptance / non-adoption" of the secondary electron data. This is performed by the vessel 12.

The operation of the scanning electron microscope according to the first embodiment will be described in detail. First, an electron beam 7 is generated from the electron gun 2, and the electron beam 7 is focused and scanned a desired number of times on the region to be observed on the sample 1 to capture image data.

Here, magnetic field data and vibration data at the time of capturing image data are detected by a magnetic field measuring device 10 and a vibration measuring device 11. And standard value (standard value can be set freely)
If there is data of the external secondary electron 8, this data is deleted by the determiner 12. Alternatively, at the time of capturing image data, the magnetic field and the vibration are monitored in real time. Then, the secondary electron data with the noise component minimized is superimposed on the observation CR.
An image is displayed at T6.

The "criterion for determining whether or not secondary electron data is adopted" in the scanning electron microscope according to the first embodiment will be described with reference to FIG. FIG. 2 is a diagram illustrating magnetic field data and vibration data at the time of detecting secondary electrons from a sample in the scanning electron microscope according to the first embodiment, and is a diagram illustrating criteria for adoption determination. .

When the magnetic field data and the vibration data at the time of detecting the secondary electrons from the sample are monitored, as shown in FIG. 2, there are cases where the magnetic field data and the vibration data are within or outside the standard. Therefore, it is determined whether the magnetic field data and the vibration data are “within the standard or out of the standard”, and except for the non-standard data (NG), the magnetic field data and the vibration data are converted into the standard data (OK). (See "Comprehensive adoption / rejection determination" in FIG. 2).

(Second Embodiment) FIG. 3 is a block diagram showing a characteristic portion of a scanning electron microscope according to another embodiment (second embodiment) of the present invention. The scanning electron microscope according to the second embodiment includes a magnetic field measuring device 1 as shown in FIG.
A switch 13 is provided between 0 and the determiner 12 and between the vibration measuring device 11 and the determiner 12, respectively. The rest is the same as the first embodiment.

In the scanning electron microscope according to the second embodiment, the magnetic field measuring device 1 is
The magnetic field data of 0 and the vibration data of the vibration measuring device 11 can be detected simultaneously or individually.

[0018]

According to the present invention, as described Shoki above, and a vibration measuring means for detecting the vibration magnetic field measuring means for detecting the variation of the magnetic field, and continuous during image data capture
Monitor magnetic field data and vibration data,
And vibration standard values, and set them to specified detection points.
Magnetic field data and vibration data are within specifications
Judge whether the data is out of the standard and delete the data outside the standard
Image data deletion function to delete data within the standard value.
It is characterized in that an image obtained by superimposing only an image is displayed on a CRT for observation , so that it is not only affected by the fluctuating magnetic field from the external environment, but also by the vibration from the external environment. The effect of obtaining an accurate image is produced.

[Brief description of the drawings]

FIG. 1 is a block diagram of a scanning electron microscope showing one embodiment (first embodiment) of the present invention.

FIG. 2 is a diagram showing magnetic field data and vibration data at the time of detecting secondary electrons from a sample in the scanning electron microscope according to the first embodiment, and showing criteria for determining acceptance / rejection.

FIG. 3 is a block diagram showing a characteristic portion of a scanning electron microscope according to another embodiment (second embodiment) of the present invention.

FIG. 4 is a block diagram of a conventional scanning electron microscope.

[Explanation of symbols]

 Reference Signs List 1 sample 2 electron gun 3 electron lens 4 polarizing coil 5 secondary electron detector 6 observation CRT 7 electron beam 8 secondary electron 9 stage 10 magnetic field measuring device 11 vibration measuring device 12 judgment device 13 switch

Claims (3)

(57) [Claims] 1. A sample is irradiated with an electron beam, secondary electrons generated from the sample are captured by a secondary electron detector, the amount of the secondary electrons is converted into brightness of a cathode ray tube, and a change in a magnetic field is detected.
Magnetic field measuring means to detect vibration and vibration measuring means to detect vibration.
In a scanning electron microscope for observing an image , continuous magnetic field data and vibration
Monitor, set the standard values of the magnetic field and vibration, and
The magnetic field data and vibration data at the detection points
Judge whether the data is within the standard or out of the standard.
An image data deletion function for deleting data outside the value is provided,
Observation CRT for superimposing only data within the specified value
A scanning electron microscope characterized by being displayed above . 2. The scanning electron microscope according to claim 1, wherein the magnetic field measuring means and the vibration measuring means can be used simultaneously or separately. 3. The scanning electron microscope according to claim 1, wherein a switch for switching is provided in the magnetic field measuring means and the vibration measuring means.